The invention relates to an installation for extinguishing fire in a unit, preferably a train with at least one railway carriage, or a tunnel, the installation comprising several spray heads, whereof a number that is smaller than the total number of spray heads can be activated according to the location of the fire in the unit, and a drive source for delivering extinguishing medium through a pipe system to the activated spray heads.
Known fire extinguishing installations are generally arranged to provide a particular mainly constant flow from every spray head or sprinkler, i.e. a spray head comprising a release means (typically an ampoule that explodes at high temperatures) irrespective of the number of spray heads and sprinklers in the fire extinguishing installation. A constant flow for each spray head thus applies, irrespective of the number of releasing spray heads in the installation. If the installation comprises a larger number of spray heads, these can be divided into fire zones in such a manner that only the zone where fire is detected is released. The flow of extinguishing medium for each spray head is constant regardless of the number of released fire zones.
In fire extinguishing installations the drive medium source that drives extinguishing medium to the spray heads has a particular effect that is assumed to provide a certain minimum flow for each spray head. If the installation comprises several spray heads, the effect of the drive medium source has to be high compared with an installation that includes a few spray heads only. This also applies if the installation has several fire zones.
Known fire extinguishing installations including several spray heads and possibly a number of fire zones are provided with a function and a construction meaning that only a part of the effect of the drive source is utilized in such a case that only a part of the spray heads (or fire zones) of the installation are released. The power available is therefore not utilized in the drive source of the fire extinguishing installation in case all the spray heads in the installation are not released.
It is commonly known that fire extinguishing must be started as efficiently as possible. This means that a particularly efficient extinguishing medium spray should initially be discharged which is able to extinguish the fire at an early stage, before the fire spreads.
It is an object of the present invention to efficiently extinguish fire by providing an installation which comprises several spray heads and which initially provides a maximum flow in the releasing spray heads, when only a part of the spray heads thereof are released.
For this object the present invention provides an installation for extinguishing fire in a unit, preferably a train with at least one railway carriage, or a tunnel, the installation comprising several spray heads, whereof a number that is smaller than the total number of spray heads can be activated according to the location of the fire in the unit, and a drive source for delivering extinguishing medium through a pipe system to the activated spray heads, wherein the drive source comprises a pump unit including a pump in order to provide a pumping pressure for pumping extinguishing medium into the activated spray head/heads, the pump unit comprising a control unit arranged to increase the extinguishing medium flow of the pump unit when the number of releasing spray heads increases in such a way that the effect of the pump unit is at least mainly kept constant. Here the term xe2x80x9ceffectxe2x80x9d refers to the working or instantaneous power.
According to a particularly preferable embodiment of the invention the spray heads are placed in the unit in a number of fire zones, which are activated separately or in groups, comprising a number of spray heads for each fire zone, and the installation comprises a number of detectors for activating the fire zones, the detectors being arranged to start delivering extinguishing medium to the respective fire zone when detecting fire, the pump unit being arranged to increase the extinguishing medium flow when the number of activated fire zones and the number of releasing spray heads increase.
The pump unit preferably comprises 2 to 10 pumps whereof a minimum number is arranged to be coupled in operation depending on the number of activated spray heads, whereby the control unit comprises a gear box for coupling the minimum number of pumps in operation. A similar pump unit preferably includes a diesel motor operating with an optimal constant number of revolutions (rpm).
The installation is particularly suitable for extinguishing fire in trains and in tunnels and the like, where a fire extinguishing installation must typically be divided into a number of fire sections.
The main advantage of the fire extinguishing installation is to enable a powerful and increased delivery of extinguishing medium from the active spray heads in such a case that only some spray heads in the installation are released. The larger the number of non-releasing spray heads, the more powerful delivery of extinguishing medium is allowed from every releasing, or active, spray head, and the releasing spray heads are therefore able to fight fire efficiently. The fire can thus be rapidly extinguished using as few as possible of the activated fire zones and using a relatively small amount of extinguishing medium, and the risk of the fire spreading is thus small. In practice it is most likely that only one fire zone or two at the most is activated.